Here we go again... I've posted a couple similar threads on this issues and it usually just ends up getting spammed by the same noobie ^knuckleheads sayin 'buh I'm ma casual and I just wanna race'... Well, if you're in this group, go find another game. You're in the minority. Tuning is and has always been a hallmark feature of Gran Turismo and is going to have to be integrated into sport mode if GTSport is going to survive.
Lock the Power & Weight ratios and leave everything else wide open to tune. Done.